Unique is a library for writing single instance application. If you
launch a single instance application twice, the second instance will
either just quit or will send a message to the running instance.

Unique makes it easy to write this kind of applications, by providing a
base class, taking care of all the IPC machinery needed to send messages
to a running instance, and also handling the startup notification side.

Unique aims to replace the BaconMessageConnection code that has been
copied by many projects and the code using Bonobo and D-Bus.
